Use of Depletion Edge Translation for High-Speed Modulation and Switching of Lightwaves

摘要

We report on our work for the period 1 March 1988 to 28 February 1989. The primary emphasis has been the Fabry-Perot modulator which we introduced in last year's interim report. Over the past year, we have completed the design, optimization and sensitivity analysis for the modulator. Experimentally, we have made good progress in improving the device performance going from a 2:1 on: off ratio for a 25 V drive to a 10:1 on: off ratio for a 7 V drive. In section V.3 of the present report. we present a brief comparison of our modulator results with those of other groups. With supplemental support from other contracts, we have also made significant advances in fundamental areas which should open new avenues for continued improvement of existing devices and lead to new device structures. We have observed a new effect in superlattices Field-Induced Stark Localization-which leads to a blue-shift in absorption edge rather than a conventional red shift. We have also observed optical properties ascribable only to quantum wire effects in quantum wire structures grown directly by molecular beam epitaxy using a process pioneered at UCSB. Both of these new structures should prove to be promising active regions for the Fabry-Perot device. Additionally, the Fabry-Perot will serve as an excellent vehicle with which to fully characterize the electro-optic properties of these new structures. (rh)